具螢光特性光敏螯合劑之開發以實現生物相關金屬離子釋放的時空控制

Abstract

金屬離子在生物系統內扮演著很重要的角色。比如說鈣離子與肌肉收縮、血液凝固相關，也是很多酵素的輔因子。鐵離子負責攜帶氧氣，鋅離子則是扮演著訊號傳送、基因表達等角色。也有很多疾病像是阿茲海默症、癲癇都與金屬離子的不正常分布相關，由此可知研究金屬離子相關的生物現象是非常重要的。然而，金屬離子相關的生物現象往往發生的相當快，因此金屬的光解螯合試劑就被開發出來。光解螯合劑提供了一種具高度時空解析度的金屬釋放策略，協助幫助研究金屬在生物過程中的功能。在本研究中，我們設計了一種螢光活化型光可解螯合劑DEACM-oNB-EDTA，其結構由乙二胺四乙酸配位基、鄰硝基苯光保護基與7-二乙氨基-4-甲基香豆素螢光團所組成。照光後，其金屬結合親和力下降三個數量級，有效釋放鋅離子，並同時活化螢光訊號以進行細胞標記。我們已透過區域選擇性照光證明其優異的時空控制能力。我們預期此策略能促進對未知鋅離子相關生物過程的探究，並可望擴展至其他金屬離子，比如說銅、鐵、鉑，用於研究具動態性且依賴金屬的細胞機制。

Metal ions play crucial roles in biological systems. For example, calcium ions are involved in muscle contraction and blood coagulation, and they also serve as cofactors for various enzymes. Iron ions are responsible for oxygen transport, while zinc ions participate in signaling and gene regulation. Abnormal metal ion distribution is associated with numerous diseases, such as Alzheimer's disease and epilepsy, highlighting the importance of studying metal-related biological processes. However, these processes often occur on rapid timescales. Therefore, photolabile metal chelators were invented. These compounds enable precise spatiotemporal control over metal release, facilitating investigations into the functions of metal ions in biological contexts. In this study, we designed a fluorescence-activatable photolabile chelator, DEACM-oNB-EDTA, which consists of an ethylenediaminetetraacetic acid (EDTA) metal-binding moiety, an ortho-nitrobenzyl (oNB) photoprotecting group, and a 7-diethylamino-4-methylcoumarin (DEACM) fluorophore. Upon light irradiation, its metal-binding affinity decreases by three orders of magnitude, leading to efficient zinc ion release and simultaneous activation of fluorescence for cellular labeling. We have demonstrated its excellent spatiotemporal resolution through regioselective irradiation experiments. We anticipate that this strategy will facilitate the exploration of previously uncharacterized zinc-related biological processes and can potentially be extended to other metal ions, such as copper, iron, and platinum, for studying dynamic and metal-dependent cellular mechanisms.